江西省锦江流域降水变化特征研究

为研究江西省锦江流域的多年降水特征,以流域的9个雨量站1957-2013年逐日降水资料为基础,对锦江流域不同地区的降水序列分别采用线性趋势、5 a滑动平均、Mann-Kendall趋势检验法,Pettitt突变检验法,累积距平,Morlet小波分析等分析方法进行研究。结果表明:①流域面上多年平均年降水量为1617.5 mm,空间分布为从上游到下游递减的特征,且每10 a以9.59 mm的趋势上升,其上升趋势主要受到中、下游的影响;20世纪90年代是锦江流域降水较多的年代,年降水量在统计年限内呈现出“偏少-偏多-偏少”的变化趋势。②季节降水量的空间分布与年降水量相同,各区域的降水量主要集中在春季,其次是夏季、冬季,秋季降水量最小;夏、秋、冬3个季节的降水量呈现上升趋势,春季降水呈现下降趋势,其中上游流域的春季、中游流域的春、夏两季的降水量的趋势变化均具有显著性,逐月降水量主要集中在4-6月,占年降水量的45.72%左右,6月降水量最大,而9-12月的降水量所占比例较小,各地区各月份所占降水百分比与流域面上相差不大。③在Pettitt检验中,各区域的春季、夏季、秋季的突变较为一致,分别为春季(1984年)、夏季(1991年)、秋季(1980年),其中中游流域的夏季突变还通过0.1显著性水平。年降水量及冬季降水量在不同区域的突变值较为分散;而从累积距平分析,年降水量其各区域较为明显的同一突变点为1991年,冬季降水为1986年。④锦江流域不同地区的年降水量主周期较为明显,均为31 a;次周期在13 a左右,但不明显。

Research on the Precipitation Variation Characteristics of Jinjiang River Basin in Jiangxi Province

In order to understand the multi-year precipitation characteristics of Jinjiang River Basin in Jiangxi Province,based on the daily precipitation data of 9 rainfall stations in the basin from 1957 to 2013,this paper uses linear trends,5-year moving average,Mann-Kendall trend test,Pettitt catastrophe test,cumulative departure and Morlet wavelet analysis to analyze the precipitation series of different regions in Jinjiang River Basin.The results show that:①The average annual precipitation over the river basin is 1617.5 mm,and the spatial distribution shows the characteristics of decreasing from upstream to downstream.The upward trend of precipitation is mainly affected by the middle and downstream areas with the trend of 9.59 mm/(10 a).The 1990s are the years with more precipitation in the Jinjiang River Basin,and the annual precipitation shows a trend of“less-more-less”in the statistical years.②The spatial distribution of seasonal precipitation is the same as that of annual precipitation.The precipitation in each region is mainly concentrated on spring,followed by summer and winter,and the least in autumn.The precipitation in summer,autumn and winter shows an upward trend,while the precipitation in spring shows a downward trend.The trends of precipitation in the upper reaches of the river basin in spring and in the middle reaches of the river basin inspring and summer are significant. The monthly precipitation is mainly concentrated on April to June,accounting for 45.72% of the annual precipitation. The precipitation in June is the largest,while the proportion of precipitation from September to December is relatively small. The percentage of precipitation in each month of each region is not significantly different from that in the river basin. ③Through Pettitt test,it can be found that the sudden changes of spring,summer and autumn in each region are more consistent, which are spring (1984), summer (1991) and autumn (1980). The sudden changes of summer in the middle reaches of the river basin are also significant at 0.1 level,and the sudden changes of annual precipitation and winter precipitation are more scattered in different regions. According to the analysis of cumulative departure, the same sudden change point of annual precipitation in each region is 1991,and the winter precipitation is 1986. ④ The main cycle of annual precipitation in different areas of the Jinjiang River Basin is relatively obvious,all of which are 31 years. The sub-cycle is around 13 years,but it is not obvious.